Controlling apparatus



Feb. 24. 19,25. K

' RUTHS ET As.

cournonmue APPARATUS Filed Nov.

Patented Feb. 24, 1925.

FICE.

JOHANNES RUTI-IS, OF DJURSEOLM', NILS PERSSON, OF LIDINGO-BREVIK, ANDCARL GUSTAF JANSON AND SIGURD MATTIAS BCKSTRM, 0F STOCKHOLM, SWEDEN, AS-SIG-NOR-S TG AKTIEBGLAGET VAORCKUMULATOR, OF STOCKHOLM, SWEDEN, A

CORPORATION OF STNEDEN.

CONTROLLING APPARATUS.

Application filed November 29, 1922.

To all whom t may concern:

Be it known that we, JOHANNES Rurrrs, NrLs PnnssoN, CARL Gusrar JANsoN,and Sironi-zn Marrras Bltcnsrnrr, subjects of the King of Sweden,residing at, respectively, Djursholm, Lidingo-Brevik, Stockholm, andStockholm, Sweden, have invented certain new and useful improvements inControlling Apparatus, of which the following is a specification.

Our invention relates to regulating mechanism and more particularly tovalve control wherein a single valve is controlled by a plurality ofindependent agencies.

ln a number of plants, particularly such as are provided with heatstorers, controlling members, for instance valves, are often to befound, said valves being adapted to be actuated by a number of impulsesindependent of each other and originating for example fromlnessurenspeeds Olnrlpr tures. By the word impulse ive mean a forcewhich is a function of a condition in that which is to be controlled.rEhe impulse is, in fact, a measure of the condition and is used toactuate a mechanism so that the mechanism moves responsively to changesin condition in that which is to be controlled. The members may beactuated directly or indirectly by conditions relating to the medium tobe controlled. As herein used the word direct designates Ythat type ofactuation wherein movement of parts is effected by means of mechanicalparts as rods, levers, etc., whereas the word indirect designates thattype of actuation wherein movement is effected through the intermediaryof a fluid such as Water or oil. The last arrangement, the indirect, isthe most common, as it is then possible to attain greater force foradjusting the regulating member` and a more accurate and sensitivecontrol.

Such indirect control is usually effected so that the impulses actuate aslide valve which controls the supply and outlet of a' pressure liquidto and from an auxiliaryor servo-motor which, in turn, adJusts theregulating member, or, if a great accuracy Serial No. 604,111.

directly actuate one or more devices, such as slide valves which, inturn, indirectly operate the servo-motor.

ln the event that the controlling appaH ratus is actuated indirectly bymeans of a pressure liquid the infiuence of the impulse on the relay isthus transmitted hydraulically to a slide valve, which, in turn,controls the pressure liquid whichoperates the servomotor so as toconsequently adjust the controlling member. The number of relaysheretofore employed corresponded to the number of impulses intended toindirectly actuate the controlling member. This makes the arrangementexpensive and renders the attendance thereof highly complicated.

The manner in which these impulses act in the controlling apparatus, maybe entirely different, for instance, it may bedesired that the maincontrolling member of the apparatus shall open if one of the impulsestends to open the same, independently of the tendency of one of. theother impulses to close the controlling member. In other cases it isdesirable that the member shall close if one of the impulses tends toclose the same independently of the tendency of another impulse to causeopening of the member. It frequently occurs in steam plants having steamstorers that a certain impulse such as a maximum pressure in the storeractuates a valve to close the same and to keep it closed regardless ofthe occurrence of other impulses tending to open the same. On otheroccasions the member has to open under all circumstances'on a certainvalue having been attained, such as the lowest speed permissible in anymachine, and so forth.

The present invention has for its object to simplify the above-mentionedcontrolling apparatus in which a plurality of relays are used forcorresponding impulses and the invention consists generally of thecombination with a main controlling member with means such as aservomotor for regulating the position of the member, means such as aslide valve for indirectly actuating the regulating means and a singledevice or relay responsive to a plurality of impulses `for indirectlycontrolling the operation of the actuating means, in such a manner thatone impulse may move the main control member in one direction regardlessof the tendency of another impulse to move the main controlling memberin another direction and regardless or relative values of the impulses,so that one impulse predominates over another.

More particularly the invention embraces the provision in a relay oi' amovable part which is responsive to a plurality of impulse receivingelements for indirectly controlling the operation of the actuating meansand also in the resilient mounting or' certain of the impulse receivingelements.

The present invention further comprises a novel relay for use inregulation oit' the above described kind.

The invention also consists oi' a control ling apparatus embodying meansfor trans mitting pressure, speed responsive and teinperature impulsesto the movable part oi the relay.

Other objects as well as`the nature, char-y acteristic features andscope of the invention will be more readily apparent from the followingdescription talen in connection with the drawings and point-ed out inthe claims forming a part of this specilication.

rlhis invention is clearly illustrated in the acccompanying drawings, inwhich z- F ig. l is a diagrammatic view oi the controlling apparatus,and

Fig. 2 is a vertical sectional view of a practical embodiment oi' thesingle relay.

Similar characters of reference are employed in all of the abovedescribed views to indicate corresponding parts.

In Fig. l, a denotes a relay on which, according to the invention, aplurality oi impulses originating in various conditions are caused toact in a manner to be described hereinbelow. B designates what we terman actuating means comprising a piston o connected with a slide valveand actuated byH a spring, and c is a servo-motor operating the maincontrol member, in the embodiment shown, a valve (Z which is inserted ina conduit e.

Arranged in the relay a is a pipe 7L provided With an outlet opening r,through which a continuously flowing stream of liquid such as oil orwater issues and is controlled by a throttling member attached to arelay arm and operated in a manner more Yt'ully described below. Thepipe 7L is connected by means of the conduit 1I, with the chamber 7cunderneath the piston Z), said chamber k being, in turn, connected withthe chamber a'. by means of the conduit Z provided with the throttlingdevice m, pressure liquid being continuously supplied to the chamber nthrough the conduit 0. The chambers lo and n are separated by thepartition ai having the slide valve s extending therethrough. Slidevalve s is shaped with `motor c through the conduit y.

a groove or recess fw, which, in the einbodiment shown, is made bycutting away a part of the slide valve co-extensive with chamber p to asmaller dimension than the remainder of the slide valve. The chamber pcommunicates with the auxiliary or servomotor c by means of the conduitg. The chamber p is separated from the chamber 'n by the partition y andfrom the outlet t by the partition The operation is as follows: Assumethat one of the impulses (in a way to be described hereinbelow) actuatesthe relay Aein such manner that the Vout-let opening' if increased so asto increase the amount of liquid iiowmg out ofthe chamber 7g, ns theamount olil liquid supplied to this chamber by the conduits Z and 0 andchamber 1r is limited by the throttling device ai, the pressure in thechamber la will sink so that the piston b moves downward through theinfluence of the spring fr; The downward movement oi" piston causes adownward movement of slide valve placing the groove Lc oppositepartition .e A'so that liquid may pass from chamber 29 to the outlet t.Pressure liquid will then liow out through the conduit g from theservo-motor c, the piston oit which then moves upwards, on account ofthe pressure of the spring u, so as to close the valve d.

On the other hand, should any ot' the impulses (in a way to be describedhere inbelow) actuate the relay ci so that the outlet opening fu wouldbe decreased, whereby a rise in the pressure in the chamber occurs, thepiston Z) will move upwards, which is also the case with the slide valves which then` admits pressureliquid from the chamber n to the chamber p,such pres sure liquid being thus supplied to the servo- Y Consequently,the pressure will rise in the servomotor, and the piston of the motor isdisplaced downwardly lso as to open the valve d.

The relay a, on which the impulses are caused to act in accordance withthe present invention, will now be described.

The speed governor 7e is adapted to actuate a movable part, in thisinstance an arm 5 from below by means of the lever 2, the rod 3 and thelever 4 so that, should the speed increase, the lever el, will move thearm 5 upwardly. The said arm 5, which is also actuated upwardly by thespring G, will vary the size of the outlet opening t'. by means ot therod '.7, according to the movement thereoiZ in one or the other direction. A tempe ature regulator;@consisting of a therinosttbi"tithelike, may influence the arm from above by means oi the lever 9, thesleeve lO, the spring l1 and the pin 12 which is slidably mounted in thesleeve 10.

The device is constructed so that the llt C ll

spring 11 is stitler than the spring 6 so that, if for instance thesleeve 10 is moved downwardly through the iniluence of the temperatureregulator 8 on rising temperatures, the spring 11 will not, orpractically not, be compressed, spring (i being compressed instead,whereby the arm 5 with the rod 7 is moved downwardly.

Moreover, a pressure (consisting in this case of the pressure before thevalve d) may act through the pipe 13 for example on a diaphragm 14,whichdiaphragm may, on a rise of the pressure, move the sleeve 15, thespring 16 and the pin 17 slidably mounted within the sleeve 15, suchdiaphragm also moving the arm 5 downwardlypn account oit the fact thatthe spring 16 is made stitl'er or stronger than the `spring 6.

rThrough the pipe 18, another pressure (in this case the pressure behindthe valve d) acts on the diaphragm 19, which actuates the pin 24, whichis slid-ably mounted in the sleeve 22, by means of the rod 20, the lever21, the sleeve Q2 and the spring By reason ot the upwardly directedpressure ot' the spring 25 on the diaphragm 19, the arm 5 may be moveddownwardly by pin 24 on a falling pressure in pipe 18. The rod 2() isextended so that on a rising pressure on the diaphragm 19 beyond acertain limit, the arm 5 will be raised by means oi the lever 26. Itthen any one ot the other impulses, for instance the impulse originatingin the ten'iperature regulator, would tend to move the arm 5 downwardly,the arrangement is such that corresponding spring, in this case spring11, will be compressed so that the above-mentioned pressure impulse,that is to say the pressure on the diaphragm 19, will be determinativeof the regulation on account of the rigid s ystem acting on the arm.Conditions will be the same it any one ot the other impulses actingabove the arm would tend to move the arm 5 downwardly and any one of theimpulses acting under the arm would then tend to move the arm upwardly.That is to say, the impulses acting from below will always be decisiveshould they tend to regulate.

It the arm 5 with the rod 7 is moved downwardly, the outlet opening o isdecreased so as to cause a rise ot the pressurr` in the chamber 7e, suchrise of the pressure resulting in the valve (Z being opened, or openedmore, as previously described.

It, again, the arm is moved upwardly, the outlet opening o is increasedso that the pressure in the chamber 7e will fall which, as describedhereinabove, results in the valve (Z beingclosed, or more nearly closed.y

It will be seen from the above that it the speed governor or thepressure prevailing on the diaphragm 19'does not actuate the arm 5 frombelow so that the valve is closed,

or more nearly closed, any one ot the impulses acting above the arm 5may control the valve, said control being such that if any one ot theseimpulses tends to open the valve, it is able to open or more fully open,even if any ot the other of these impulses acting from above would tendto close the valve. That the impulses acting below tne arm will alwaysbe decisive should any ol' these impulses tend to close the valve, isrendered possible, as stated above, by these impulses being caused toiutluence the arm 5 through a rigid system, whereas the impulses actingabove the said arm influence the latter by means of a resilient system.

lli it be assumed, for example, that ,the pressure before the valve CZrises, this will influence the diaphragm ll, the diaphragm lll movesdownwardly and by the intermediary of the sleeve 15, the spring 16, andthe pin 17, the arm 5 is moved downwardly and the valve d is opened,provided ot course that none ot the impulses acting from below tends toclose the valve by pressing the arm 5 upwardly.

It' namely, to take an example, the pressure behind the valve, whichinfluences the diaphragm 19, would now have a maximum Value, or rise tosuch value, the arm cannot be moved downwardly, or it it be moveddownwardly, it is again forced upwardly `so that the valve will thenagain be closed,

as described above. By changing the lengths ot' the pins or rodspertaining to the various impulses, the regulation may be adjusted toditl'erent values.

It will appear from above that the valve opens in the present caseshould the pressure before the same rise beyond a certain value, whichtakes place independently of whether the pressure behind the valve wouldrise on this occasion, provided such latter pressure has not attained acertain limiting value: likewise, it will open it the pressure behindthe same would tall independently thereof whether the pressure beforethe valve would then fall and thus tend to close the valve.

As is readily apparent the action ot the predominating impulse isabsolute and positive regardless ot the relative values ot the impulses,for example, the relative pressure on the two sides otl the main controlmember; the action is absolute regardless ot the absolute value ot theimpulse which is overcome. The action ot' the pressure behind the valvein closing or opening the same is not affected by the pressure be't'orethe valve, through all ranges o't this latter pressure.

lt will be seen from the above that an unlimited number of impulses maybe provided and that all conceivable combinations for the control ot'the valve may be carried out according to this principle.

Fig. 2 illustrates another embodiment of the relay In this embodiment,the main controlling member or valve Z of Fig. l is to be controlled bytwo pressures, so that the member shall always open if any one of thepressure impulses tends to open the same, but in case the one pressurehas attained a certain maximum value, the valve is to remain closed orbe closed.

rIwo pressures act on the diaphragms and 3l adapted to actuate the arm39 by means ot' the sleeve 32, the sprng 33 and the pin 34. slid-ablyarranged within the sleeve 32 and provided with the adjustable abutmentsand 36, as well as b y means of the bracket 3S the length of which isadapted to be adjusted by the screw 37, the outlet opening o being thuschanged by the arm 39. The arm abuts against the fixed support and isretained in contact therewith and also in contact with the pin Sli bythe spring 4l.

The bracket 38 is attached to the da phragm 30 by means ot the screw 37,whereas the sleeve is in loose contact with the diaphragm 31.

The pressures acting on the diapliragms 30 and 3l are eiiective, becauseot the resiliency ot' the diaphragn'is.

It is assumed that the pipe 71, having the outlet opening o providedtherein is in communication with the chamber 7s (Fig. l), as describedhereinabove; it the outlet opening is then increased for some reason orother, the valve (Z will thus be closed, as previously described, but itthis opening is decreased, the said valve will open more or less.according to such decrease.

rEhe device operates in the Jfollowing manner:

It is assumed that the pressure on the diaphragm 31 is increased forsome reason or other, which results in the sleeve 32 being moved to theleft. Now, the spring 38 is constructed so as to overcome the springatl, by reason of which the pin 3st is also moved io the 'leit and thearm 39 is forced to turn about the fixed support 40 so that the openingo is decreased, which, as previously die- .icribed, results in the valvel being somewhat opened. Thus the valve will in this case open it thepressure on the diaphragm 3l rises beyond a certain value and,consequently, the valve (Z may serve as a scalled over-flow valve. Byreason et the motion between the abutmcnts 35 and 3G and the bracket 3Sit is evident lthat the pressure acting on the diaphragm 3l may regulatethe valve within wide limits, independently of the pressure acting onthe diaphragm 30.

It' the pressure on the diaphragm 30 falls, the bracket 38 is moved tothe left on account of the recoiling of the diaphragm; if the pressurefalls so far that the bracket 38Y strikes against the abutment 3G, thepin 3st' sliding loosely within the sleeve 32 will be` 30 rises to sucha value that the bracket 88 is moved to the right so as to strike theabutment 35, this will result in the spring 33 being compressed, and thepin Bat being moved to the right, which causes the opening /v toincrease and the valve (l to close, entirely independently thereottwhether the pressure on the diaphragm 3l would at the same time tend tomove the pin in the opposite direction so as to open the valve.

By reason of the abutmcnts and 36 being adjustable on the pin 34 andowing to the length of the bracket 38 being adapted to be altered withthe aid et the lettand right-handed screw 37, an adjustment ot thecontrol is rendered possible within wide limits.

That we claim as new and desire to secure by Letters Patent of theUnited States is:

1. In a control apparatus adapted to be influenced by separate impulses,the combination ot a. main control member, liquid pressure operatedmeans to regulate the position of said member, liquid pressure operatedmeans to control the operation of said first mentioned means, separatestreams ot liquid under pressure for operating each o'l said means and asingle device responsive to a plurality of impulses for indirectly controlling the operation of the actuating means.

In a control apparatus adapted to be influenced by a plurality otimpulses, the combination ot a conduit, a valve in said conduit, aliquid pressure operated servomotor to actuate said valve, an actuatingmeans, a relay, two streams of liquid, one passing trom said actuatingmeans to said servo-motor and controlled by said actuating means, theother passing from said actuating means to said relay and controlled bysaid relay, an arm associated with said relay` a plurality ci'mechanisms associated with said arm, each responsive to a separateimpulse. l

3. In a control apparatus adapted to be influenced by a plurality ofimpulses, the combination of a main control member, liquidpressureoperated means to control said member, actuating means for indirectlyactuating the first mentioned means, a single arm to control the secondmentioned means, a rigid mechanism adapted to move said arm, a secondmechanism adapted to move said arm, said second mechanism having twoparts and a spring arranged between said parts.

4. In a control apparatus adapted to be influenced by separate impulses,the combination of a main control member, a liquid pressure operatedservo-motor to control the position of said control member, liquidpressure operated means to control said servomotor, a relay to controlsaid liquid pressure operated means, an arm associated with said relayactuated by a plurality of impulses, means for etfecting the movement ofsaid arm by one impulse in one direction and, at the same time,overcoming the tendency of another impulse to move the arm in anotherdirection independent. of absolute values ot the impulse which isovercome, so that the first impulse predominates over the secondimpulse.

In a control apparatus adapted to be influenced by a plurality ofimpulses, the combination of a main control member, liquid pressureoperated means to control the operation ot said main control member, asecond liquid pressure operated means to control said iirst mentionedmeans, said second means comprising a slide valve, chambers associatedwith said slide valve, a continuous throttled connection between two ofsaid chambers and a spring acting on said slide valve, a relay tocontrol said second means, an arm associated with said relay, separatemechanisms, each operated by a separate impulse and acting independentlyon said arm.

6. In a control apparatus adapted to be influenced by a plurality ofimpulses, the combination of a main control member, liquid pressureoperated means to control the position of said member, a second liquidpressure operated means to control said irst means, a relay, acontinuous stream of liquid flowing from said second means to saidrelay, an arm controlling said stream and a plurality of impulses actingon said arm.

7. In a control apparatus adapted to be influenced by a plurality oimpulses, the combination of a main control member, means for regulatingthe position of said member, a second means for indirectly actuating theregulating means` said second means including two parts adapted, undercertain conditions to move together and under other conditions to haverelative movement.

8. In a control apparatus adapted to be influenced by a plurality ofimpulses, the combination of a conduit, a valve in said conduit, asingle device to indirectly control said valve, means operating on saiddevice to regulate the valve in response to the pressure in said conduitin front of said valve and means operating o-n said device to open saidvalve when the pressure in said conduit behind said valve falls below apredetermined value even when said first means tends to close the valveand independent of absolute pressures in front ot' the'valve.

9. In a control apparatus adapted to be influenced by a plurality ofimpulses, the combination of a conduit, a valve in said conduit, aliquid pressure operated servoinotor to control said valve, liquidpressure operated actuating means to control liow of liquid to saidservo-motor, a single device to control the pressure in said actuatingmeans, means operating on said device to regulate the valve in responseto the pressure in said conduit in front of said valve and meansoperating on said device to open said valve when the pressure in saidconduit behind said valve t'alls below a predetermined value even whensaid first means tends to close the valve and independent of absolutepressures in front ot' the valve.

l0. In a control apparatus adapted to be influenced by a plurality yoitimpulses, the combination of a conduit, a valve in said conduit, aliquid pressure operated servomotor to control said valve, liquidpressure operated actuating means to control flow 'of liquid to saidservo-motor, a single device to control the pressure in said actuatingmeans, means operating on said device to regulate the valve in responseto the pressure in said conduit in front of said valve and meansoperating on said device to close said valve when the pressure in saidconduit behind said valve rises above a predetermined value even whensaid first means tends to close the valve and independent of'absolute/pressure in front 'of the valve.

11. In 'axcontrol apparatus adapted to be influenced by a plurality ofimpulses, the combination of a conduit, a valve in said conduit, asingle device to indirectly control said valve, means operating on saiddevice to regulate the value in response tothepressure in said conduitin 'friritoIf/said valve and meanshoperating lon said device to closesaid valve Vwhen the pressure in said conduit behind said valve risesabove a predetermined valueteven when said first means tends to open thevalve and independent of absolute pressures in front of the valve.

12. In a control apparatus adapted to be inuenced by a plurality ofimpulses, the combination of a conduit, a valve in said conduit, asingle device to indirectly control said valve, means operating on saiddevice to regulate the valve in response to the pressure in said conduitin front of said Avalve, means operating yon said device responsive tothe pressure behind said valve and means operating on said deviceresponsiyeto a speed.,

lSIiihacontrol apparatus adapted totbe influenced by a plurality olimpulses, the combination of a conduit, a valve in said conduit, asingle device to indirectly control said valve, means operating on saiddevice to regulate the valve in response to the piles sure in saiduconduit .in froiiotvsaiddvalve, means operatingwo'n said deviceresponsive to the pressure behind said valve and means operating onsaid., device responsive to a temneratuta 14. In a Vcontrol apparatus,adapted to be influenced by a plurality of impulses, the combination ofa conduit, a valve in said conduit, a liquid pressure operatedservomotor controlling said valve, liquid pres sure operated actuatingmeans to control the servo-motor, relay mechanism to control theactuating means, means responsive to the preS/S L1 1L..ll1il l,oqnwdpitin `front 'of the valve 't'factuate saidwinechanism, means responsive tothe pressure behind said valve to aetuate said mechanism independentlyof the pressure before the valve and a spe'ed responsive device adaptedto actuate said mechanism. M"

l5. In a control apparatusadapted to be influenced by a plurality otimpulses, the combination of a main control member, a servo-motor tocontrol said member, actuating means to control said servo-motor` arelay to control said actuating means, a fluid communication betweensaid actuating means and said relay, and a single device responsive to aplurality of impulses associ` ated with said relay.

16. In a control apparatus adapted to be influenced by a plurality otimpulses, the combination of a main control member, a liquid pressureoperated servo-motor to control said member, liquid pressure operatedactuating means to control the passage o1 liquid to and return from saidservo-motor, a single mechanism to control said actuating meansresponsive to a plurality7 of impulses.

17. In a controlk apparatus adapted to be influenced by a plurality otimpulses, the combination of a main control member, liquid pressureoperated means to control sain member, a grooved slide valve to controlthe passage of liquid to said means, a relay to control liquid toactuate said slide valve, said relay comprising a single arm actuated bya plurality ot impulses.

18. In a control appa atus. adapted to be iniiuenced by a. plurality oi3impulses. the combination ot' a main control member, a cylinder, apiston in said cylinder, liquid pressure actuating means to actuate saidpiston` a single member responsive to a plurality of impulses to controlsaid actuating means.

19. In a control apparatus adapte-d to be influenced byla plurality ofimpulses, the combination of" a conduit, a valve in said conduit, aliquid pressure operated servoinotor to control sai-d valve, liquidpressure operated actuating means to control said servo-motor, a relay,a continuous stream ot liquid i'lowing from said actuating means throughsaid relay, a single arm controlling the said stream, mechanismresponsive to a plurality ot impulses acting on sai-d arm to regulatethe valve by the pressure in front thereof and to open the valve whenthe pressure behind the valve falls below a predetermined value, meansto close the val-ve by the pressure behind the valve when the pressurebefore tends to open the valve.

Q0. A relay for control apparatus comprising an arm, a spring acting tomove the arm in one direction, a pin acting on said arm` a sleeve Jforsaid pin, means to atleet relative movement of said pin an-d sleeve, apressure responsive device adapted to move said sleeve, a mechanismresponsive to another pressure acting on said arm and adaptvvd atcertain times to oppose and overcome the action oit the pin on the arm.

21. A relay for control apparatus comprising an arm, a spring acting tomove the arm in one direction, a pin acting on said arm, a sleeve forsaid pin, means to ettect relative movement of said pin and sleeve, apressure responsive device adapted to move said sleeve, a mechanismresponsive to another pressure acting on said arm and adapted at certaintimes to oppose and overcome the action of the pin on the arm and acontinuously flowing stream of liquid controlled by said arm.

22. A relay for control apparatus comprising an arm, a spring acting tomove the arm in one direction, a pin acting on said arm, a sleeve forsaid pin, means to etect relative movement of said pin and sleeve, apressure responsive device adapted to move said sleeve, a mechanismhaving parts positioned on both sides oit' said arm and adapted to movethe arm in both directions.

28. A relay for control apparatus comprising an arm. resilientmeansadapted to move the arm in one direction. mechanism responsive topressure adapted to aetuate the -aJ-m in another direction. mechanismresponsive to pressure adapted to move the arm in both directions, andmeans whereby the latter mechanism overcomes the action oll the tirstmechanism.

24. A relay tor! control apparatus comprising an arm. resilient meansadapted to move the arm in one direction. mechanism responsive topressure adapted to actuate the arm in another direction, mechanismresponsive to pressure adapted to move the arm in both directions, andmeans whereby the latter mechanism overcomes the action of the lirstmechanism and a continuously flowing stream oi liquid controlled by saidarm.

,25. A relay for control apparatus comprising an arm, resilient meansadapted to lOO move the arm in one direction, mechanism adapted to movethe arm in another direction, mechanism adapted to move the arm in bothdirections, a plurality ot diaphragnis cach responsive to a separatepressure impulse acting on said meehanisn'is.

26. A relay for control apparatus comprising an arm, resilient meansadapted to move the arm in one direction, mechanism adapted to move thearm in another direction, mechanism adapted to move the arm in bothdirections, a plurality of diaphragins each responsive to a separatepressure impulse acting on said mechanisms and a continuously flowingstream of liquid controlled by said arm.

27. A relay for control apparatus comprising an arm, mechanism actuatedby an impulse to move the arm and regulate the position of the same, asecond mechanism responsive to a second impulse normally in active butadapted to overcome the first mechanism and control the position ot therm for extreme valu-es of the second impulse.

Q8. A relay for control apparatus comprising an arm, mechanism actuatedby an impulse to move the arm and regulate the position of the same, asecond mechanism responsive to a second impulse normally inactive butadapted to overcome the iirst mechanism and control the position ot thearm for eXtreme values of the second impulse, and a continuously flowingstream of liquid controlled by said arm.

29. A relay for control apparatus comprising, an arm, a plurality otmechanisms each responsive to a separate impulse acting on said arm,means whereby one ot said mechanisms can always move said arm in onedirection regardless ot the tendency of a second mechanism to move thearm in the opposite direction and regardless ot absolute values of theimpulse to which the second mechanism is responsive.

30. A relay for control apparatus comprising, an arm, a plurality ofmechanisms each responsive to a separate impulse acting on said arm,means whereby one of said mechanisms can always move said arm in onedirection regardless ot the tendency ot a second mechanism to move the'arm in the opposite direction and regardless ot absolute values of theimpulse to which the second mechanism is responsive and a continuouslyflowing stream of iluid controlled by said arm.

31. In a control apparatus` a main control member, a relay to indirectlycontrol sait main control member, a continuously iowing stream of liquidin said relay and a single movable part responsive to a plurality ofimpulses to throttle said continuously flowing stream of liquid.

32. In a control apparatus adapted to be influenced by a plurality oitimpulses, a Conduit, a valve in said conduit, means to regu-l late thevalve responsive to the pressure in the conduit in front of the valve,means responsive to the pressure in the conduit behind the valve toclose said valve when said pressure behind the valve rises above apredetermined value even when the lirst means tends to open the valveand independent oi' absolute pressures in iront of the valve and meansresponsive to the pressure in the conduit behind the valve to open saidvalve when said pressure behind the valve falls below a predeterminedvalue even when said first means tends to close the valve andindependent ot absolute pressures in front o't' the valve. l

33. In a control apparatus adapted to be influenced by a plurality ofimpulses, a conduit, a valve in said conduit, means to control the valveresponsive to the pressure in the conduit in iront of the valve, meansto control the valve responsive to the pressure behind said valve andmeans responsive to the pressure in the conduit behind the valve toclose said valve when the said pressure behind said valve rises above apredetermined value even when the firstmeans tends to open the valve andindependent of absolute pressures in the conduit in front of the valve.

in a control apparatus the combina.- tion et a main control member,means for regulating the position ot said member, means `tor actuatingthe regulating means, a relay to control said actuating means, a movablepart associated with said relay, and a plurality of mechanisms eachresponsive to a separate impulse acting on said movable part. one ofsaid mechanisms being made ot two parts, one ot which is movablerelative to the other and resilient means interposed between said twoparts.

In a control apparatus adapted to be iniluenced by a plurality ofimpulses, the combination ot a main control member, liquid pressureoperated means to control said member7 actuating` means `for indirectlyactuating the first mentioned means, a single arm to control the secondmentioned means` a rigid mechanism adapted to move said arm, a secondmechanism adapted to move said arm, said second mechanism having twoparts and a resilient means arranged between said parts.

In testimony whereof we ailix our signatures in presence ot twowitnesses.

JOHANNES Raras. Nits Pressen. CARL cUsrAr Janson. Sietse tiernassciisraM. lllitnesses a Erre HALGER, Nits Hanson.

